JPH033027Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a vertical linearity correction system that enables simultaneous correction control of vertical amplitude and vertical linearity at both vertical deflection frequencies for two different vertical deflection frequencies in a cathode ray tube display device. Regarding circuits.

In cathode ray tubes, if the sawtooth current applied to the vertical deflection coil is distorted, the top or bottom of the screen will expand or contract. To solve this problem, linearity correction of the sawtooth wave is performed in the vertical amplifier circuit. The causes of distortion in the vertical deflection coil current include distortion of the oscillation waveform, nonlinearity of the transistor, and output transformer, and various circuits have been devised to correct these distortions. Generally, nonlinear distortion is corrected by negative feedback using the emitter resistance of the vertical output circuit, or by inserting a low resistance into the emitter of the transistor of the vertical amplifier circuit, and passing a vertical deflection coil current through it to generate a negative feedback voltage. . In addition, for distortion of the oscillation waveform, the output is fed back to the vertical amplifier circuit, integrated by an integrating circuit, and added to the oscillation output. Figure 1 is a circuit diagram when the distortion of the oscillation waveform of the vertical oscillation circuit 1 is corrected by the integrating circuit 2.The integrating circuit 2 generates a rising waveform that is opposite to the downward sloping waveform of the oscillation waveform. Corrects linearity. The lower the frequency (vertical deflection frequency) of the vertical synchronization signal, that is, the longer its period (coinciding with the period T of the sawtooth wave), the greater the distortion of the oscillation waveform of the vertical oscillation circuit 1.
The time constant of the integrating circuit 2 that corrects this must be reduced. Incidentally, in the case of the television broadcasting system, the vertical deflection frequency is switched between different predetermined known constant values, but in cathode ray tube display devices, the frequency to be switched varies depending on the model and is not unified. Therefore, the vertical linearity is appropriate at one vertical deflection frequency, but becomes inappropriate at another vertical deflection frequency. In this case, readjust by turning the vertical linearity (V.LINE) volume or change the circuit constants. I have to do something.

Therefore, in the vertical deflection circuit of this type of cathode ray display device, a circuit that can simultaneously correct and control the vertical amplitude and vertical linearity at any of the two different vertical deflection frequencies is used. Therefore, the technical challenge is how to realize this circuit without a complicated circuit configuration, how to make it possible with a simple control system, and how to realize a circuit layout that is easy to integrate. It was hot.

The present invention was proposed in order to solve the above-mentioned problems, and in a vertical deflection circuit applied to a cathode ray display device that requires high resolution, it is possible to determine which vertical deflection frequency Regarding frequency, vertical amplitude and vertical linearity can be corrected and controlled simultaneously with one control signal. The object of the present invention is to provide a vertical linearity correction circuit that enables simple control using a signal source and realizes a circuit arrangement that is easy to integrate.

The present invention will be explained below with reference to the drawings. FIG. 2 is a circuit diagram of a vertical deflection circuit of a display device to which a vertical linearity correction circuit according to an embodiment of the present invention is applied.

_T1 is the input terminal for the vertical synchronization signal. 10 is an integrated circuit (for example, T.I.'s SN74122) which is a retriggerable monostable multivibrator.
+B ₁ is the power supply voltage supplied to the integrated circuit 10, which is this monostable multivibrator. _C1 ,
_C2 is a capacitor for noise absorption. C ₃ and R ₁ are a capacitor and a resistor, respectively, that set the reference vertical deflection frequency for retriggering.
_VR1 is a variable resistor that adjusts the pulse width of the output pulse of the integrated circuit 10, which is a monostable multivibrator, and the pulse width is determined together with the resistor _R2 and the capacitor _C4 . TR ₁ is turned on by the output of pin 12 of integrated circuit 10, which is a monostable multivibrator;
The transistor is the first switching element to be turned off, and _R3 is its protection resistor. 20 is a vertical deflection integrated circuit (for example, NEC μPC1031H). +B ₃ is a power supply voltage supplied to this vertical deflection integrated circuit 20. R ₄ , R ₅ are resistors, VR ₂ ,
VR ₃ is a variable resistor, and C ₉ is a capacitor. These values determine the amount of vertical amplitude adjustment, and this adjustment is performed using variable resistors VR ₂ and VR ₃ . R ₁₂ , VR ₅ , and C ₁₂ are resistors, variable resistors, and capacitors that respectively determine the amount of vertical synchronization (V.HOLD) frequency adjustment, and the adjustment is performed by variable resistor VR ₅ . C ₁₃ , C ₁₄ , C ₁₅ ,
Both _C16 are capacitors for noise absorption.
R ₁₃ , R ₁₄ , and R ₁₅ are protection resistors. DY is the vertical deflection coil, R ₁₀ is its protection resistor. _C8 is a positive feedback capacitor and _R9 is a protection resistor.
C ₁₀ and C ₁₇ are positive feedback capacitors. _R11 ,
VR ₄ and the first capacitor C ₇ are a resistor, a variable resistor, and a capacitor for vertical linearity (V.LINE) adjustment, respectively, and are performed by the variable resistor VR ₄ . 30
is a vertical linearity correction circuit according to an embodiment of the present invention. IN ₁ is an inverter circuit. TR ₂ is the second
The switching element is a transistor, and + _B2 is its power supply. R ₆ , R ₇ and R ₈ are protective resistors.
_C6 is a second capacitor for vertical linearity (V.LINE) adjustment together with resistor _R11 , variable resistor _VR4 , and capacitor _C7 . D ₁ is a diode, and when transistor TR ₂ is turned on and a low level signal flows in, it becomes an open state, and when transistor TR ₂ is turned off and a high level signal flows in, it becomes a short circuit state and capacitor C ₆ becomes a capacitor. Connected in parallel to C ₇ .

Next, the operation of the vertical deflection circuit having the above configuration will be explained. When a vertical synchronizing signal having a vertical deflection frequency lower than the reference frequency set in the integrated circuit 10, which is a monostable multivibrator, is input from input terminal _T1 , the integrated circuit 10, which is a monostable multivibrator, has a higher level than pin 12. continues to output the signal. This allows the transistor
TR ₁ is turned on and the vertical amplitude is adjusted by variable resistors VR ₂ and VR ₃ . Furthermore, the high level signal from pin 12 is input to the inverter circuit _IN1 and changes to low level. Transistor TR ₂ is therefore in the off state, diode D ₁ is shorted and capacitor C ₆ is connected in parallel with capacitor C ₇ .
In other words, the time constant of the sawtooth wave applied from the vertical oscillation circuit to the vertical output circuit of the vertical deflection integrated circuit 20 can be adjusted by R·(C ₆ +C ₇ ), where R is the combined resistance of the resistor R ₁₁ and the variable resistor VR ₄ . and become smaller,
Vertical linearity is adjusted accordingly. Next is the input terminal
When the vertical deflection frequency of the vertical synchronization signal input from _T1 is higher than the reference frequency, the output of pin 12 of the integrated circuit 10, which is a monostable multivibrator, remains at a low level. As a result, the transistor _TR1 is in an off state, and the vertical amplitude is adjusted only by the variable resistor _VR3 . and inverter circuit
The output of IN ₁ becomes high level and the transistor
TR ₂ is on, diode D ₁ is open,
That is, capacitor C ₆ is not connected to capacitor C ₇ . That is, the time constant of the sawtooth wave applied from the vertical oscillation circuit to the vertical output circuit of the vertical deflection integrated circuit 20 is R・C ₇ (R is the resistance R ₁₁ and the variable resistance VR ₄
The vertical linearity is adjusted accordingly.

As explained above, the present invention utilizes the output of a monostable multivibrator that outputs a signal for switching a variable resistor for vertical amplitude adjustment, so that the vertical deflection frequency of the vertical synchronization signal can be adjusted to the standard of a monostable multivibrator. If it is smaller than the frequency, another capacitor is connected in parallel to the capacitor of the vertical linearity correction circuit, and if it is larger, it is disconnected, so the vertical deflection frequency of the vertical synchronization signal crosses the reference frequency. When the vertical deflection frequency is small, the correction amount for vertical linearity is large, and when the vertical deflection frequency is large, the correction amount is small. Therefore, it has the effect that the vertical linearity automatically always falls within a certain standard. Further, according to the present invention, both the resistor for amplitude correction and the capacitor for vertical linearity correction are connected at the same time by the output signal of the monostable multivibrator circuit 10 which is output in response to changes in the vertical deflection frequency. As a means for separating, a first switching means TR1 of a non-contact active element is used.
and second switching means TR2, and share the only output signal of the monostable multivibrator circuit 10 as a control signal, so that vertical amplitude and vertical linearity can be corrected and controlled simultaneously with one control signal. When correcting and controlling vertical amplitude and vertical linearity at the same time, it is possible to perform simple control with a single signal source without requiring a complicated circuit configuration, and realizes a circuit layout that is easy to integrate. Accordingly, it is possible to provide a vertical linearity correction circuit with the following features.

[Brief explanation of the drawing]

FIG. 1 is a correction circuit and a waveform diagram of a vertical oscillation circuit, and FIG. 2 is a circuit diagram of a vertical deflection circuit of a display device to which a linearity correction circuit according to an embodiment of the present invention is applied. 20...Vertical oscillation circuit, waveform shaping circuit, VR ₂ ,
VR ₃ , R ₄ , R ₅ ... circuit network, C ₆ ... capacitor,
TR ₁ ...First switching means, TR ₂ ...Second switching means
10. A monostable multivibrator (integrated) circuit.

Claims (1)

[Claims for Utility Model Registration] In a vertical deflection circuit of a cathode ray tube display device, which is equipped with at least a vertical oscillation circuit and a waveform shaping circuit, when the frequency of a vertical synchronizing signal input from the outside is lower than a predetermined reference frequency, a monostable multivibrator circuit that continues to output a signal for the output signal; a plurality of circuit networks consisting of variable resistors and resistors for adjusting the amplitude of the output signal of the vertical oscillation circuit; first switching means for responsively switching to select one of the plurality of circuit networks; and an integrating circuit forming part of the waveform shaping circuit for correcting the linearity of the output waveform of the oscillation circuit. On the other hand, in response to the output signal of the monostable multivibrator circuit, the capacitor is connected in parallel to increase the time constant of the integrator circuit, and when this output signal is given, the capacitor is connected to the integrator circuit. connection,
a second switching means for releasing the connection when the output signal is not applied; and the first switching means and the second switching means apply the same signal to the monostable multivibrator circuit as a control input signal. A vertical linearity correction circuit characterized in that the output signals of the two are shared and used.